1. Field of the Invention
The present invention relates in general to surgical dressings and, in particular, to a dressing for the prevention of alveolar osteitis following the removal of a tooth or cyst.
2. Description of the Prior Art
Development of alveolar osteitis, commonly known as dry socket, following the removal of a tooth or maxillary cyst is a well known phenomena. Symptoms which usually accompany a dry socket include a severe pounding and throbbing pain that is generally unrelenting and usually begins within forty-eight to seventy-two hours after the surgery. A dry socket is most likely to occur with the surgical removal of impacted teeth, and in particular, with the removal of the mandibular third molars. It has been estimated that between ten and forty percent of all such extractions eventually develop a dry socket.
Currently the accepted procedure to aid in the prevention of a dry socket includes minimizing unnecessary trauma during surgery, irrigating the extraction site following surgery with a saline solution, use an antibiotic dressing following extraction, and avoiding vasoconstrictors, such as infiltration anesthesia. If a dry socket still occurs, the accepted treatment includes irrigation of the extraction site with a saline solution to flush debris out the extraction site, placement of a socket dressing using a medicated iodoform gauze, for example Bipp's Paste, changing the dressing every twenty-four to forty-eight hours until symptoms abate, and, on occasion, prescription of a broad spectrum antibiotic. Because of the severe pain associated with a dry socket, nerve block anesthesia may be required to properly place the dressing.
Generally, it is believed that the syndrome consists of a blood clot forming and then subsequently being lost between the third and fifth day following surgery. It has also been theorized that this premature dislodgment of the blood clot may be due to either physical dislodgment, lack of proliferation of capillary buds into the blood clot, or a chemical lysis of the blood clot. Regardless of its cause, dry socket is a prevalent and painful condition.
U.S. Pat. No. 3,952,414 to Shovers et al, discloses a method for the prevention of osteitis and for the prevention of atrophy of alveolar bone which consists of embedding an implant into the bony cavity, such as a cystic cavity or alveolus after tooth extraction. The preformed implant is a solid body of tissue-compatible material and has a smooth unbroken exterior surface defining a bulbous, gibbous shape which generally follows the contour of the cavity. In one application, the implant is placed in the extraction socket following the removal of the tooth. The size and placement of the implant are chosen to be sufficient to locate the occlusal end of the implant approximately three to four millimeters beneath the height of the bony tissue. The normal healing processes are said to be adequate to entirely surround the implant with trabecular bone tissue and to form an occlusal layer of boney tissue above the implant, similar to steel reinforced concrete. However, the implant is not absorbed by the body over time and is not moldable to minimize pressure at the affected site.
U.S. Pat. No. 3,919,773 to Freeman discloses a dental implant composition and placement method which includes a moldable, polymerizable material which is inserted into the tooth socket immediately after the tooth has been extracted. Being moldable, the material conforms to and substantially fills the socket. Prior to inserting the moldable material into the socket, the surface of the material is first coated or dusted with particulate calcium sulfate which becomes embedded in the outer surface of the moldable material. The calcium sulfate is dissolvable in body fluids so that eventually minute voids develop in the outer surface of the hardened implant. These voids are said to promote tissue attachment to firmly anchor the implant. However, the implant is not absorbed by the body and it is intended as an anchor for subsequent attachment of a crown or other appliance and is not directed at preventing the occurrence of a dry socket.
Previously, a number of materials have been used to help correct various types of bone defects. For example, plaster of Paris has been considered as a material to fill defects in bone or as a bone substitute since the late 1800's. The plaster usually is completely absorbed by the body and normal bone fills the cavity with only a slight reaction to the plaster of Paris. Plaster of Paris implants are known to be the most quickly absorbed of most implants taking on an average 4.7 weeks. In contrast, autogenous bone implants require approximately seven weeks to be absorbed. Liquid plaster is normally used to fill the defect. Where indicated, an oral antibiotic can be incorporated directly into the plaster of Paris which acts as a medicinal vehicle. As the plaster of Paris is absorbed by the body, the antibiotic granules can be released. An extensive review of plaster of Paris as a bone substitute is reported by Bahn S. L.:Plaster: A Bone Substitute. Oral Surg., Oral Med. and Oral Path. 21: 672-681 (May) 1966.
Labourg and Biou were the first to report using plaster of Paris to fill the wounds remaining after odontectomy of impacted third molars as well as other osseous defects in the mandible and maxilla. Labourg and Biou first formed plugs of plaster of Paris of various size and then utilized the plug that best fit the size of the bony cavity to fill the extraction site or cystic pocket. The plaster of Paris plug was shaped to the form of the bony cavity using the same instruments as used for a bone graft to make the filling as complete as possible. Tissue above the filled cavity was then closed by making deep points to draw together and hold the tissues in place. Labourg and Biou noted that the tolerance of plaster was very good and that the plaster is absorbed within three or four weeks as shown by clinical examination and by x-ray (Labourg. L. and Biou, C.: The Embedding of Plaster of Paris in Surgical Cavities of the Jaws, Sem. Hop. Paris 37: 1195-1197, 1961). However, their implant was not moldable to minimize pressure at the affected site and was not directed at preventing the occurrence of a dry socket.
Plaster of Paris also has been used as a periodontal surgical dressing (Bier, S. J.: Plaster of Paris: A Periodontal Surgical Dressing, N.Y. State D. J. 36: 347-352 (June-July) 1970). Bier noted that the presence of plaster of Paris in the defect apparently discourages a rapid downgrowth of epithelium and permits connective tissue regeneration. Bier also noted that none of the cases under study demonstrated postoperative pain, swelling, or secondary infection. Bier believed that a space filler, such as the plaster, facilitates regeneration by helping to form a healthy clot. Thus, the risk of granulation tissue breakdown or necrosis and delayed healing may be decreased by the use of space-occupying material to restrict the primary hematoma to the periphery of the lesion. However, the plaster was only intended as temporary space filler and was not directed at preventing the occurrence of a dry socket. In addition, it is believed that Bier's composition would be absorbed by the body too quickly to permit regeneration of bone in the affected area.
Plaster of Paris also has been used with solid and porous hydroxylapatite particles as a medicinal vehicle to faciliate manipulation of the hydroxylapatite particles during placement on the alveolar ridge and as a means of limiting their initial migration (Frame, J. W., Rout, P. G. J., and Browne, R. M.: Ridge Argumentation Using Solid and Porous Hydroxylapatite Particles with and Without Autogenous Bone or Plaster: J. Oral Maxillofac. Surg. 45: 771-777, 1987). However, the plaster was only intended as a temporary medicinal vehicle to aid in the construction of the denture bearing surface and was not directed at preventing the occurrence of a dry socket.
It has thus become desirable to develop a composition and method for preventing the occurrence of dry socket, which at the same time, is moldable to prevent unnecessary pressure at the affected site and is absorbed into the body to permit regeneration of bone in the affected area.